[Qemu-devel] U-Boot

[Vlad Lungu <vlad@comsys.ro>]

Vlad Lungu wrote:

lol, replying to myself

> Blue Swirl wrote:
> 
>>
>> Someone could port OpenBIOS or LinuxBIOS to MIPS.
>>
> 
> Well, just FYI:
> 
> I sort-of-ported U-Boot to Qemu (-M mips). Network performance sucks for 
> some reason (hard enough that tftp-booting a kernel is impossible) and I 
> didn't have time to investigate this yet. But I guess that porting to 
> (-M malta) should not be that hard, and I think there is some PCI 
> support already in U-boot.
> 

Reports of poor network performance have been greatly exagerated. 
Apparently, what it happens is :

- qemu doesn't respond with a next-server or server-name in DHCP, apparently
- U-Boot uses broadcast in this case as the server address
- things don't quite work

Setting IP by hand or using tap for networking and configuring DHCP on 
the host correctly allows loading bt TFTP (or even nfs-booting with 
tap). I can boot a vmlinux with embedded ramdisk (a couple of Megs) in 
maybe 10 seconds. Still getting RX timeouts, but it's no big deal.

I will polish the thing a little and post an update in 1-2 weeks max.
Maybe we can have a bootrom for MIPS shipping with Qemu, after all. Even 
for malta.

Vlad